The present invention relates to a control system operative to monitor fluid pressure in order to control an electric apparatus in response to the pressure of the fluid. Specifically, the present invention is adapted as a pump control apparatus used to control the operation of a pump, such as a submersible pump in a water well. The pump control apparatus of this invention is therefore directed to providing a freeze-proof control unit for a submersible pump that eliminates many problems confronting existing pump control systems.
The typical construction of a conventional modern pump system involves the placing of a submersible pump at the bottom of a well casing located at the source of the water to be pumped to the earth's surface. The water pipe from the submersible pump extends upwardly to terminate at a releasable elbow, called a pitless adaptor, which is located below the frost line for the geographical region of the well. A discharge pipe then extends laterally of the pitless adaptor and then upwardly into a pump control house which contains a relief valve and pressure switch to electrically control the pump. A water reservoir or pressure tank is connected to this discharge pipe so that a quantity of water is readily available for use. The pressure switch which provides the appropriate controls for the submersible pump is connected thereto by means of electrical conduit which exits the pump house, passes through a well cap and extends downwardly into the well casing to the submerged pump.
A problem is encountered by this control system where the pump control house is used. Specifically, the pressure switch directly monitors the pressure in the water discharge pipe and is thus in fluid contact with water as the water passes along the pipe in the pump control house. Since the pump house may be located in remote regions above ground, sub-freezing temperatures may be encountered. This can cause the pressure switch to freeze either in the open or closed position. If the switch freezes in the closed position, so the pump runs, it is possible for water flooding to take place since the submersible pump remains in constant operation. Also, the submersible pump may be burnt out due to its constant running with no discharge. Should the pressure switch freeze in the open position, the pump will not run so that no water is available at the water use station. In automatic animal feeding lots, for example, this can deny the animals access to water. In remote locations, this can cause great inconvenience to the rancher since water must be hauled to the animals, without which they may die.
In addition to the inconveniences caused by subfreezing temperatures, the placement of the pump controls in the control house has other disadvantages. Since it is difficult to make a pump control house air tight, dust can infilterate the pump control house, and insects or other vermin may get into the pump control house and damage the pressure switch. Further, due to the cost of constructing a pump control house, or well pit, some wells allow the pump control apparatus, including the pressure switch, to be exposed to the elements. This can cause damage and malfunction of these units and, in addition, the units may be damaged by livestock or other animals that bump into them.
Accordingly, there is a need for a pump control apparatus which can eliminate the traditional pump control house while, at the same time, better seal the environment of the pump controls against dust, insects, vermin and the like. There is a need for such a pump control unit that resists breakdown in sub-freezing temperatures. There is need for such a pump control apparatus that is easy to use, inexpensive to construct and which allows easy access to the submersible pump located within a water well casing.